Continuous strip pickling method and apparatus



July 18, 1939. R. A. CRITTEN 2,166,583 CONTINUiJUS STRIP PICKLING METBOD AND APPARATUS I 4 Sheets-Sheet 1 Filed Jan. 15, 1938 July 18, 1939. R. A. CRITTEN 2,166,583

CONTINUOUS STRIP PICKLING METHOD AND APPARATUS 4 Sheets-Sheet 2 [mania EOBEET 46HFOED CE/TTE/v 'Filed .Jan. 15, 3,938

July 18, 1939. R. A. CRlTTEN cpnnimous STRIP PICKLING METHOD AND APPARATUS Filed Jan. 15, 1938 4 Sheets-Sheet 3 July 18, 1939.- R. AICRITTEN 2,166,583

CONTINUOUS STRIP PICKLING METHOD AND APPARATUS Filed Jan. 15, 1938 4 Sheets-Sheet 4 Patented July 18, 1939 UNITED STATES PATENT OFFlCE CONTINUOUS STRIP PICKLING METHOD AND APPARATUS This invention relates to a method andapparatus for pickling continuous strip metal and, more particularly, to an improved method of recharging the pickling tanks with pickling solutions.

6 In pickling strip metal, it is usually the practice to provide a series of pickling tanks arranged in end-to-end relationship, each having a pickling solution therein of the proper acid concentration through which the strip metal is adapted to pass.

10 After these pickling solutions have been used for a while they become greatly reduced in their acid concentration and have to be replaced with fresh pickling solutions of the proper acid concentration. Heretofore, it has been the usual practice to empty the used pickling solutions from each of the tanks, recharge the tanks with fresh water and acid to the proper acid concenpickling solutions'without suspending pickling 30 operations.

It is another object of the invention to provide an apparatus for pickling continuous strip metal whereby the pickling solutions in each of the tanks can be easily and quickly changed and 5 replaced with pickling solutions of the proper acid concentration.

.ilt'is a further object of this invention to provide pickling tanks for pickling continuous strip metal which will keep the metal completely im- 40 nieifsed in the solutions therein as it passes continuously therethrough.

' Various other objects and advantages of my invention will vmore fully appear during the course of the following specification, and will be 45 particularly pointed'out in the appended claims.

"In the accompanying drawings I have shown, for the purpose of illustration, one embodiment which my invention may assume in practice.

,In the-drawingsf i -lir'ures 1, 1 and 1 together constitute a plan I pi." the improved apparatus of my invention for v pickling continuous strip metalf ,Ei'giires 2 2' and 2 together constitute a side elevation of the same; and,

Figure 3 is a sectional view taken on the lines IIIIII of Figures 2, and 2 There is shown in the drawings three pickling tanks 2 arranged substantially on the same level for holding suitable pickling solutions and a 5 fourth tank 3 arranged preferably at a lower level. These tanks are consecutively arranged in line in end-to-end relationship and have a guideor direction roll 4 positioned between each of them over which the strip is adapted to pass 10 as it moves from one tank. to the other.

There is rotatably mounted in each of the tanks adjacent each end thereof adjustable holddown rollers 5. These rollers are adapted to keep the strip of metal immersed in the pickling solutions in the respective tanks as the strip passes therethrough. The shafts 6 of these rollers are rotatably mounted in bearing-like guide members I which are, in turn, movably mounted in suitable guideways 8 in the sides of the tanks. The outer ends of the shafts of these rollers are mounted in bearing members 9 which are connected to the top end of each of'the screws Ill arranged along the side of the tanks. There is disposed on each of the screws ID a gear l2 which is adapted to'be driven by suitable worm-gears I3 mounted on drive shafts l4 which, in turn, are driven by a motor I5 through a transmission l6. These screws are adapted to raise and lower the rollers in the tanks through the above described mechanism. With such an arrangement these rollers can be adjusted relative to the height of the pickling solution in the tanks so as to keep the metal strip completely immersed in the pickling solutions as it passes therethrough, and substantially the full length of the tank can be utilized for pickling. Also, with such an arrangement these rollers can be raised, if desired, a considerable distance above the solution to permit the strip to be brought out of the solution which is an advantage when pickling operations are to be suspended for any length of time.

At the entering end of the line of tanks there is preferably arranged a stitcher I1, stitcher pinch-rolls l8, 8. wet looper-pit l9, strip-guides 20, and a pair of power-driven pinch-rolls 2|. At the delivering end of the line of tanks there is arranged preferably a pair of power driven pinch-rolls 22, a wet loope'r-pit 23, another pair of power-driven pinch-rolls 24, a hot water strip 59 rinsing tank 25, a stitch-shear 26, an oiling unit 21" and a strip 'coiler 2B.

line of tanks produce a drag on the strip so as to keep the strip taut as it passes through each of the tanks. The wet looper-pit 23 at the delivering end takes the place of the conventional cold water rinse tank. Such a pit eliminates the stopping of the strip in the pickling tank and allows the continuous pickling of the strip while the stitch is being sheared from the strip.

There is arranged along one side of the line of tanks a drain line 29 which is connected to the used pickling solution tank 3 at 30 and to each of the tanks 2 at 3|. This drain line 29 is preferably arranged so that it slopes from the tanks 2 toward the tanks 3. Preferably along the other side of the tanks there is arranged an elevated auxiliary water tank 32 which is connected to each of the tanks by means of a pipe line 33. This tank is used for preheating the water before it enters the pickling tanks. There is not shown any means for heating the water in the tank, but any Suitable means may be employed.

When the acid concentration of the pickling solutions in the pickling tanks 2 is materially reduced and unfit for any appreciable amount of further .use, the solution in each of these tanks is successively conveyed through the drain line 29 into the dump tank 3 and a fresh pickling solution made up successively in each of the tanks after they are emptied. With this arrangement the required number of pickling tanks, in this case three, would be available for use at all times,

thus permitting continuous operation of the linewithout material loss in production. while a fresh pickling solution was being made successively in each of the tanks 2. The location of the dump tank 3 at a lower elevation than the other three and the drain line at a slope is advantageous in that it permits the used pickling solutions to flow from the tanks by gravity, thereby eliminating the need of pumps for handling the hot pickling solutions.

The auxiliary hot water tank is, of course, provided for heating the water prior to the dumping of a tank. With hot water available, a tank can be dumped and a fresh pickling solution mixed within a very short time.

While I have shown and described an embodiment of my invention, it will be understood that this embodiment is merely for the purpose of il-' lustration and description and that various other forms may be devised within the scope of my invention, as defined in the appended claims.

I claim:

1. Apparatus for pielfling a continuous strip of metal including a plurality of pickling tanks through which the strip is adapted to pass, one of said tanks being positioned lower than the others, independently controlled means for conveying the waste pickling solution from each of said tanks to the lower positioned tank, a'container for preheating the water, and means for conveying said heated water from said container into each of said tanks to mix fresh pickling solutions therein.

2. Apparatus for pickling a continuous strip of metal including a number of pickling tanks having a pickling solution therein of the proper acid concentration for properly pickling said strip, an extra tank having a used pickling solution therein, means for moving the strip through all of said tanks, means for draining the used-pickling solution from said last-mentioned tank, and independently controlled means for conveying the pickling solutions from each of said tanks when it is unfit for further use into said extra tank.

3. The method of changing the pickling solutions in a plurality of consecutively arranged pickling tanks for pickling continuous strip metal, each of said pickling tanks having a pickling solution therein of the proper acid concentration for properly pickling the strip as it continuously passes therethrough and an extra tank through which the strip also passes during the pickling thereof comprising emptying the used pickling solutions from each of the tanks,

one at a time, into said extra tank, and recharg- 4. The method of changing the pickling solution in a plurality of consecutively arranged pickling tanks for pickling continuous strip metal with at least one 'of the tanks being positioned at a lower level,than the others, comprising emptying the used pickling solution from each of said other tanks successively and independently into said lower tank by means of gravity and recharging each of the tanks successivelywithin a fresh pickling solution of the proper acid concentration while the strip is being continuously pickled and moving therethrough.

5. The method of changing the pickling solution in a plurality of consecutively arranged pickling tanks for pickling continuous strip metal with at least one of the tanks being positioned at a lower lever than the others, each of said higher positioned pickling tanks having initially disposed therein a pickling solution of the proper acid concentration for properly pickling the strip as it continuously passes therethrough comprising emptying the used pickling solution after it has fallen below the required acid concentration from each of said higher positioned tanks successively into said lower positioned pickling tank by means of gravity and recharging each of said higher positioned pickling tanks successively with a pickling'solution 'olihe proper acid concentration while the strip is passing continuously through all of the tanks and .being pickled.

ROBERT ASHFORD CRITTEN. 

